System and method for transferring heat between two units

ABSTRACT

A thermal switching device is presented. The thermal switching device includes a plurality of serpentine capillaries having a first end and a second end, where the first end is configured to be operatively coupled to a heating unit and the second end is configured to be operatively coupled to a cooling unit, and where the plurality of serpentine capillaries is configured to transfer heat from the heating unit to the cooling unit by circulating a working fluid in the plurality of serpentine capillaries.

BACKGROUND

Embodiments of the present specification relate generally to cryogenics, and more particularly to a thermal switching device in a cryogenic setup.

Thermal switching devices are important components in many cryogenic applications, such as in a magnetic resonance imaging (MRI) application. Typically, thermal switching devices are used to make or break a thermal contact between components within a cryostat. In one example, the thermal switching devices are used in cryostats that are employed in high-field nuclear magnetic resonance (NMR) applications. In another example, the thermal switching devices are employed in cryostats that are configured for use in NMR and MRI magnet related systems. Also, the cryostats may be employed in dynamic nuclear polarization (DNP) applications that are used in magnetic resonance (MR) imaging. Further, the cryostat may include components such as a cryocooler and/or a sorption pump. The sorption pump may generate heat that is transferred to the cryocooler via the thermal switching devices. However, any leakage of heat while breaking the thermal contact between these components may affect overall the performance and efficiency of the system. Also, any parasitic leakage of heat in the system may lead to undesirable changes in operational cycles or operational modes within the system.

Therefore, there exists a need for robust thermal switching devices that aid in preventing leakage of heat into the system while breaking the thermal contact between the components in the system, while also facilitating high heat transfer and quick cooling of the components in the system.

In a conventional thermal switching device, one or more moving parts may be used to make or break a thermal contact between the various components in the system. These moving parts in the thermal switching device may prevent leakage of heat in the system. However, the moving parts undergo wear and tear over a period of time and may degrade the performance of the thermal switching device. Also, the cost involved in maintaining these parts in the thermal switching device is very high, which in turn increase the overall cost of the thermal switching device. Moreover, as the moving parts are involved in making or breaking the thermal contact, there may be delay in switching the thermal switching device from an ON state to an OFF state or vice-versa, which in turn reduces a switching ratio of the thermal switching device.

BRIEF DESCRIPTION

In accordance with aspects of the present specification, a thermal switching device is presented. The thermal switching device includes a plurality of serpentine capillaries having a first end and a second end, where the first end is configured to be operatively coupled to a heating unit and the second end is configured to be operatively coupled to a cooling unit, and where the plurality of serpentine capillaries is configured to transfer heat from the heating unit to the cooling unit by circulating a working fluid in the plurality of serpentine capillaries.

In accordance with a further aspect of the present specification, a method for transferring heat from a heating unit to a cooling unit is presented. The method includes coupling a plurality of serpentine capillaries between the heating unit and the cooling unit, where the plurality of serpentine capillaries is partially filled with a working fluid. Also, the method includes circulating the working fluid in the plurality of serpentine capillaries to transfer heat from the heating unit to the cooling unit.

In accordance with another aspect of the present specification, a polarizer system is presented. The polarizer system includes a thermal switching device including a plurality of serpentine capillaries arranged to form a closed loop, where the plurality of serpentine capillaries is partially filled with a working fluid. Also, the thermal switching device includes a heating unit operatively coupled to a first end of the plurality of serpentine capillaries and configured to heat the working fluid at the first end of the plurality of serpentine capillaries. Further, the thermal switching device includes a cooling unit operatively coupled to a second end of the plurality of serpentine capillaries and configured to condense the working fluid at the second end of the plurality of serpentine capillaries, where the working fluid is circulated in the closed loop of the plurality of serpentine capillaries to transfer heat from the heating unit to the cooling unit when a temperature of the working fluid is above a threshold temperature. In addition, the polarizer system includes a sorption pump operatively coupled to the heating unit. Also, the polarizer system includes a thermal bus operatively coupled to the cooling unit.

DRAWINGS

These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:

FIG. 1 is a diagrammatical representation of a polarizer cryogenic setup, in accordance with aspects of the present specification;

FIG. 2 is a diagrammatical representation of a thermal switching device, in accordance with aspects of the present specification; and

FIG. 3 is a flow chart illustrating a method for providing a thermal connection between a heating unit and a cooling unit, in accordance with aspects of the present specification.

DETAILED DESCRIPTION

As will be described in detail hereinafter, various embodiments of exemplary systems and methods for providing a thermal connection between components are presented. By employing the methods and the various embodiments of the system described hereinafter, a thermal switching ratio of a thermal switching device may be significantly improved. Moreover, cost for manufacturing the thermal switching device and also cost of maintaining the thermal switching device may be substantially reduced.

Turning now to the drawings and referring to FIG. 1, a diagrammatical representation of a polarizer system 100, in accordance with aspects of the present specification, is depicted. The polarizer system 100 may be used for production of contrast agents that are used in magnetic resonance imaging (MRI) of a subject. In one example, the contrast agents may be used for metabolic studies of the subject. In one embodiment, the polarizer system 100 may be used for polarizing the contrast agent so as to enhance a magnetic resonance (MR) image of a subject. The polarizer system 100 may employ cryogenics to reduce a temperature of the contrast agent during polarization of the contrast agent.

In a presently contemplated configuration, the polarizer system 100 may include a sorption pump 102, a cryocooler 106, a condenser 108, and a storage unit 110. It may be noted that the polarizer system 100 may include other components, and is not limited to the components shown in FIG. 1. The cryocooler 106 may be used to cool one or more superconducting magnets (not shown) that are used in the MRI systems. Also, the cryocooler 106 may be employed to reduce the temperature of the contrast agents that are used to enhance imaging of a subject.

Further, the sorption pump 102 may be coupled to the condenser 108 via a first channel 114. Also, the sorption pump 102 may be coupled to the cryocooler 106 and the condenser 108 via a thermal bus 112. The thermal bus 112 may be used to transfer heat from the sorption pump 102 to the cryocooler 106 and/or the condenser 108 in an operational mode.

As depicted in FIG. 1, the sorption pump 102 may include a working fluid 120 and a determined amount of charcoal 122. In one example, the sorption pump 102 may be configured to store the working fluid in a gaseous form. Moreover, in one embodiment, the charcoal 122 in the sorption pump 102 may be heated. Alternatively, in another embodiment, the sorption pump 102 may be heated by using a heater 116. In one example, the heater 116 may be disposed within the sorption pump 102. However, in another example, the heater 116 may be positioned outside the sorption pump 102. Further, in the example where the sorption pump 102 is heated, the stored working fluid 120 may be expelled from the charcoal 122 and/or the sorption pump 102 and may be channeled to a desired location in the polarizer system 100. In the embodiment of FIG. 1, the first channel 114 may be employed to direct the expelled working fluid from the sorption pump 102 to the condenser 108. Moreover, the expelled working fluid may be condensed in the condenser 108. Further, the condensed working fluid may then be directed from the condenser 108 to the storage unit 110 via a second channel 118.

In another embodiment, the sorption pump 102 may be cooled. When the sorption pump 102 is cooled, vapor pressure above this liquid in the storage unit 110 may be reduced. This reduced vapor pressure may in turn aid in cooling the storage unit 110 to a target operating temperature. In one example, the target operating temperature may be below 1 K.

Furthermore, when the sorption pump 102 is heated, the heat from the sorption pump 102 may be transferred or leaked to other components, such as the superconducting magnets (not shown), the cryocooler 106, and the condenser 108 in the system 100. This leakage of heat may affect the performance of the various components in the system 100. In one example, the leaked heat may increase the temperature of the superconducting magnets, which in turn causes the superconducting magnets to switch out of their superconducting state. Thus, it is desirable to isolate the sorption pump 102 from the other components in the system 100 when the sorption pump 102 is heated.

To overcome the problems noted hereinabove, the system 100 may include an exemplary thermal switching device 104. The thermal switching device 104 may be positioned between the sorption pump 102 and the thermal bus 112, in one example. The thermal switching device 104 may be used to isolate the sorption pump 102 from the other components in the system 100. Particularly, when the thermal switching device 104 is turned to an ON state, the sorption pump 102 may be thermally coupled to the cryocooler 106 and the latent heat of the sorption pump 102 may be transferred to the cryocooler 106 via the thermal switching device 104. Similarly, when the thermal switching device 104 is turned to an OFF state, the sorption pump 102 may be thermally decoupled from the cryocooler 106, thereby preventing any transfer of heat generated in the sorption pump 102 to the cryocooler 106. Transitioning the thermal switching device 104 between the ON and OFF states will be explained in greater detail with reference to FIG. 2. Thus, by employing the thermal switching device 104, the sorption pump 102 may be thermally coupled or decoupled from the cryocooler 106 and the thermal bus 112. Also, the leakage of heat from the sorption pump 102 to the other components in the system 100 may be substantially reduced.

Referring to FIG. 2, a diagrammatical representation 200 of a thermal switching device, in accordance with aspects of the present specification, is depicted. The thermal switching device 200 may be representative of the thermal switching device 104 of FIG. 1. The thermal switching device 200 in one embodiment may include a plurality of serpentine capillaries 202, a heating unit 204, a cooling unit 206, an inlet valve 208 and a reservoir 211. The heating unit 204 may include an evaporator that may be configured to generate heat. In one embodiment, the plurality of serpentine capillaries 202 may be coupled to the heating unit 204 and the heating unit 204 may be coupled to the sorption pump 102 of FIG. 1. Alternatively, in another embodiment, the plurality of serpentine capillaries 202 may be directly coupled to the sorption pump 102. Similarly, the cooling unit 206 may include a condenser that may be configured to absorb the heat generated by the heating unit 204. In one embodiment, the plurality of serpentine capillaries 202 may be coupled to the cooling unit 206 and the cooling unit 206 may be coupled to the thermal bus 112 of FIG. 1. However, in another embodiment, the plurality of serpentine capillaries 202 may be directly coupled to the thermal bus 112.

Further, the serpentine capillaries 202 may be configured to aid in transferring the heat from the heating unit 204 to the cooling unit 206. In particular, the serpentine capillaries 202 may be configured to thermally couple the heating unit 204 to the cooling unit 206 when the thermal switching device is operated in an ON state. Similarly, the serpentine capillaries 202 may be configured to thermally decouple the heating unit 204 from the cooling unit 206 when the thermal switching device is operated in an OFF state.

In a presently contemplated configuration, the serpentine capillaries 202 may be coupled between the heating unit 204 and the cooling unit 206. Particularly, a first end 212 of the serpentine capillaries 202 may be coupled to the heating unit 204, while a second end 214 of the serpentine capillaries 202 may be coupled to the cooling unit 206. Moreover, in one embodiment, the serpentine capillaries 202 may include pulsating heat pipes (PHPs) 210. The PHPs 210 may be U-shaped capillaries or pipes that are connected to each other to form a closed loop between the heating unit 204 and the cooling unit 206, as depicted in FIG. 2. In one example, 32 U-shaped capillaries or pipes may be connected to each other to form 64 turns in the closed loop. The length of these U-shaped pipes 210 may be in a range from about 50 mm to about 200 mm.

It may be noted that one or more dimensions of the pulsating heat pipes may be customized depending upon a choice of the working fluid used in the serpentine capillaries 202. In one example, the dimensions of the serpentine capillaries may include an inner diameter, an outer diameter, a length, and the like. For example, if the working fluid is neon, hydrogen, or nitrogen, the pulsating heat pipes may have large inner and outer diameters. Also, in one embodiment, the pulsating heat pipes may have an inner diameter in a range from about 0.3 mm to about 2 mm and an outer diameter in a range from about 0.5 mm to about 2.5 mm when helium is used as a working fluid in the serpentine capillaries 202.

Moreover, the serpentine capillaries 202 may be partially filled with a working fluid. The serpentine capillaries 202 may include an inlet 216 that is coupled to the reservoir 211 via a first channel 218. In one embodiment, the reservoir 211 may be configured to store the working fluid 213 in a gaseous form. Moreover, in one example, the working fluid 213 may be helium. Also, the inlet valve 208 may be coupled to the first channel 218 at the inlet 216 of the serpentine capillaries 202. The inlet valve 208 may initially be used to control the flow of the working fluid from the reservoir 211 to the serpentine capillaries 202. In one example, a volume of the working fluid in the serpentine capillaries 202 may be in a range from about 0.5 ml to about 20 ml.

Further, when the working fluid 213 in the reservoir 211 is heated to a desired temperature, a pressure of the working fluid 213 may increase above a desirable pressure. This increase in the pressure of the working fluid 213 may cause the working fluid 213 to flow from the reservoir 211 to the serpentine capillaries 202. Subsequent to the serpentine capillaries 202 being at least partially filled with the working fluid 213, the inlet valve 208 may be closed to prevent any further flow of the working fluid 213 from the reservoir 211 to the serpentine capillaries 202. In addition, surface tension effects in the working fluid may result in the formation of slugs of liquid 220 interspersed with bubbles of vapor 222 in the working fluid. It may be noted that the terms “slugs of liquid” and “liquid slugs” may be used interchangeably and the terms “bubbles of vapor” and “vapor bubbles” may be used interchangeably in the present specification.

In addition, to operate the thermal switching device 200 in the ON state, the serpentine capillaries 202 may be partially filled with the working fluid and the working fluid may be heated to a temperature above a threshold temperature. In one example, the threshold temperature may be in a range from about 20 K to 50 K. In one embodiment, the heating unit 204 may be used to heat the working fluid at the first end 212 of the serpentine capillaries 202. Particularly, the working fluid may absorb the heat generated in the heating unit 204 and this absorbed heat may increase the temperature of the working fluid above the threshold temperature. This increase in the temperature of the working fluid may in turn result in an increase in the number or volume of the vapor bubbles 222 in the working fluid at the first end 212 of the serpentine capillaries 202. Also, a meniscus 224 may be formed at an interface between the vapor bubbles 222 and the liquid slugs 220. Formation of the meniscus may in turn increase the pressure of the working fluid to a pressure above a threshold pressure. In one example, the threshold pressure may be in a range from about 150 kPa to 200 kPa. Also, in one embodiment, the pressure of the working fluid that is greater than the threshold pressure may be referred to as a capillary pressure.

Moreover, with the increase in the pressure of the working fluid, the vapor bubbles 222 and the liquid slugs 220 in the working fluid may be pushed towards the cooling unit 206. It may be noted that the cooling unit 206 may be employed to cool the working fluid at the second end 214 of the serpentine capillaries 202. The working fluid may be cooled to reduce the pressure of the working fluid to a value below the threshold pressure. This decrease in the pressure of the working fluid in turn results in a collapse of the vapor bubbles 222 in the working fluid at the cooling unit 206. This growth and collapse of the vapor bubbles 222 in the working fluid may result in an oscillating motion of the working fluid in the serpentine capillaries 202. This oscillating motion of the working fluid may further aid in circulating the working fluid in the serpentine capillaries 202 between the heating unit 204 and the cooling unit 206. Implementing the thermal switching device 200 as described hereinabove aids in circulating the working fluid in the serpentine capillaries 202 without the use of a pumping unit or any other mechanical means for circulating the working fluid in the plurality of serpentine capillaries 202.

Moreover, this circulating motion of the working fluid in the serpentine capillaries 202 may thermally couple the heating unit 204 to the cooling unit 206 to transfer heat from the heating unit 204 to the cooling unit 206. Particularly, when the working fluid is circulated in the serpentine capillaries 202, the working fluid may absorb heat from the heating unit 204 and release the absorbed heat to the cooling unit 206. Thus, when the thermal switching device 200 is operated in the ON state, the heating unit 204 may be thermally coupled to the cooling unit 206 and the heat may be transferred from the heating unit 204 to the cooling unit 206.

In a similar manner, to operate the thermal switching device 200 in the OFF state or to switch the thermal switching device 200 from the ON state to OFF state, the heating unit 204 may be prevented from heating the working fluid at the first end 212 of the serpentine capillaries 202. This in turn causes the temperature of the working fluid at the heating unit 204 to drop below the threshold temperature. Also, the pressure of the working fluid may drop below the threshold pressure. This drop in the pressure of the working fluid may impede the circulation of the working fluid in the serpentine capillaries 202, which in turn prevents the transfer of heat from the heating unit 204 to the cooling unit 206.

Thus, when the thermal switching device 200 is operated in the OFF state, the heating unit 204 may be thermally decoupled from the cooling unit 206 and hence impedes the transfer of heat from the heating unit 204 to the cooling unit 206. It may be noted that the thermal switching device 200 may be frequently switched between the ON state and the OFF state by varying the temperature of the working fluid around the threshold temperature. In one example, the thermal switching device 200 may have a switching ratio of about 5000. In one another embodiment, the working fluid in the serpentine capillaries 202 may be removed or directed back to the reservoir 211 to operate the thermal switching device 200 in the OFF state.

Referring to FIG. 3, a flow chart illustrating a method 300 for transferring heat from a heating unit to a cooling unit, in accordance with aspects of the present specification, is depicted. For ease of understanding, the method 300 is described with reference to the components of FIG. 2. The method begins at step 302, where the plurality of serpentine capillaries 202 may be coupled between the heating unit 204 and the cooling unit 206. In one embodiment, the first end 212 of the serpentine capillaries 202 may be operatively coupled to the heating unit 204, while the second end 214 of the plurality of serpentine capillaries 202 is operatively coupled to the cooling unit 206. Moreover, these serpentine capillaries 202 may be U-shaped pipes 210 that are connected to each other to form a closed loop between the heating unit 204 and the cooling unit 206. The serpentine capillaries 202 may be at least partially filled with a working fluid. In one example, the working fluid may be helium.

Subsequently, at step 304, the working fluid may be heated at the first end 212 of the serpentine capillaries 202. In one embodiment, the heating unit 204 may be used to heat the working fluid in the serpentine capillaries 202. As previously noted, the heating unit 204 may be configured to heat the working fluid to operate the thermal switching device 200 in the ON state. The working fluid in the serpentine capillaries 202 may be heated to increase a temperature of the working fluid, which in turn increases the vapor bubbles 222 and the liquid slugs 220 in the working fluid at the first end 212 of the serpentine capillaries 202. Also, with the increase in the temperature of the working fluid, the vapor bubbles 222 and the liquid slugs 220 may be pushed towards the second end 214 of the serpentine capillaries 202.

In addition, at step 306, the working fluid may be condensed at the second end 214 of the serpentine capillaries 202. In one example, the cooling unit 206 may be used to cool the working fluid at the second end 214 of the serpentine capillaries 202. Particularly, the working fluid may be cooled to reduce the pressure of the working fluid to a value below a threshold pressure, which in turn aids in collapsing the vapor bubbles 222 in the working fluid at the second end 214 of the serpentine capillaries 202.

Furthermore, as indicated by step 308, the working fluid may be circulated in the serpentine capillaries 202 to transfer heat from the heating unit 204 to the cooling unit 206. In one embodiment, the heating unit 204 may be configured to heat the working fluid to increase the temperature of the working fluid above the threshold temperature. In one example, the threshold temperature may be in a range from about 20 K to 50 K. When the working fluid is heated above the threshold temperature, the number or volume of the vapor bubbles 222 in the working fluid may be increased at the first end 212 of the serpentine capillaries 202. Also, the meniscus 224 may be formed at an interface between the vapor bubbles 222 and the liquid slugs 220. The formation of meniscus 224 may in turn increase the pressure of the working fluid above the threshold pressure. Also, this increase in the pressure of the working fluid may push the working fluid having the vapor bubbles 222 and the liquid slugs 220 towards the cooling unit 206.

Further, at the cooling unit 206, the pressure of the working fluid may be reduced to condense or collapse the vapor bubbles 222 in the working fluid at the second end 214 of the serpentine capillaries 202. This growth and collapse of the vapor bubbles 222 in the working fluid may result in an oscillating motion of the working fluid within the serpentine capillaries 202. This oscillating motion of the working fluid may further aid in circulating the working fluid in the serpentine capillaries 202 between the heating unit 204 and the cooling unit 206 to transfer the heat from the heating unit 204 to the cooling unit 206.

In addition, the working fluid may be impeded from circulating in the plurality of serpentine capillaries 202 to prevent transfer of heat from the heating unit 204 to the cooling unit 206. In one example, the heating unit 204 may be used to impede the circulation of the working fluid in the serpentine capillaries 202. The heating unit 204 may be stopped from heating the working fluid at the first end 212 of the serpentine capillaries 202. This in turn causes the temperature of the working fluid at the heating unit 204 to drop below the threshold temperature. Also, the pressure of the working fluid may drop below the threshold temperature. This drop in the pressure of the working fluid may impede the circulation of the working fluid in the serpentine capillaries 202, which in turn prevents the transfer of heat from the heating unit 204 to the cooling unit 206. Thus, by varying the temperature of the working fluid in the thermal switching device 200, the heating unit 204 and the cooling unit 206 may be thermally coupled or decoupled from each other.

The various embodiments of the system and method aid in thermally coupling or decoupling the heating unit from the cooling unit. Since the working fluid is used for thermally coupling or decoupling the heating unit from the cooling unit, the cost of manufacturing the thermal switching device, and also the cost involved in maintaining the thermal switching device may be substantially reduced.

While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention. 

1. A thermal switching device, comprising: a plurality of serpentine capillaries having a first end and a second end, wherein the first end is configured to be operatively coupled to a heating unit and the second end is configured to be operatively coupled to a cooling unit, and wherein the plurality of serpentine capillaries is configured to transfer heat from the heating unit to the cooling unit by circulating a working fluid in the plurality of serpentine capillaries.
 2. The thermal switching device of claim 1, wherein the plurality of serpentine capillaries is configured to transfer the heat from the heating unit to the cooling unit when a temperature of the working fluid is above a threshold temperature.
 3. The thermal switching device of claim 2, wherein the plurality of serpentine capillaries is configured to circulate the working fluid in the plurality of serpentine capillaries without use of a pumping unit.
 4. The thermal switching device of claim 1, further comprising: a reservoir configured to house the working fluid; and an inlet valve operatively coupled to the reservoir and the plurality of serpentine capillaries and configured to permit flow of the working fluid between the reservoir and the plurality of serpentine capillaries.
 5. The thermal switching device of claim 1, wherein one or more dimensions of the plurality of serpentine capillaries are customized based on a choice of the working fluid.
 6. The thermal switching device of claim 1, wherein an inner diameter of the plurality of serpentine capillaries is in a range from about 0.3 mm to about 2 mm.
 7. The thermal switching device of claim 1, wherein an outer diameter of the plurality of serpentine capillaries is in a range from about 0.5 mm to about 2.5 mm.
 8. The thermal switching device of claim 1, wherein a volume of the working fluid in the plurality of serpentine capillaries is in a range from about 0.5 ml to about 20 ml.
 9. The thermal switching device of claim 1, wherein the plurality of serpentine capillaries comprises pulsating heat pipes coupled to each other to form a closed loop between the heating unit and the cooling unit.
 10. The thermal switching device of claim 9, wherein a length of each of the pulsating heat pipes is in a range from about 50 mm to about 200 mm.
 11. A method for transferring heat from a heating unit to a cooling unit, comprising: coupling a plurality of serpentine capillaries between the heating unit and the cooling unit, wherein the plurality of serpentine capillaries is partially filled with a working fluid; and circulating the working fluid in the plurality of serpentine capillaries to transfer heat from the heating unit to the cooling unit.
 12. The method of claim 11, wherein coupling the plurality of serpentine capillaries comprises forming a closed loop of the plurality of serpentine capillaries between the heating unit and the cooling unit.
 13. The method of claim 11, wherein circulating the working fluid comprises oscillating the working fluid in the plurality of serpentine capillaries by increasing a temperature of the working fluid at a first end of the plurality of serpentine capillaries and decreasing the temperature of the working fluid at a second end of the plurality of serpentine capillaries.
 14. The method of claim 13, wherein circulating the working fluid comprises circulating the working fluid in the plurality of serpentine capillaries when a temperature of the working fluid is above a threshold temperature.
 15. The method of claim 14, further comprising impeding the circulation of working fluid in the plurality of serpentine capillaries when the temperature of the working fluid is below the threshold temperature.
 16. The method of claim 11, further comprising coupling an inlet valve to the plurality of serpentine capillaries to permit flow of the working fluid between a reservoir and the plurality of serpentine capillaries.
 17. A polarizer system, comprising: a thermal switching device comprising: a plurality of serpentine capillaries arranged to form a closed loop, wherein the plurality of serpentine capillaries is partially filled with a working fluid; a heating unit operatively coupled to a first end of the plurality of serpentine capillaries and configured to heat the working fluid at the first end of the plurality of serpentine capillaries; a cooling unit operatively coupled to a second end of the plurality of serpentine capillaries and configured to condense the working fluid at the second end of the plurality of serpentine capillaries, wherein the working fluid is circulated in the closed loop of the plurality of serpentine capillaries to transfer heat from the heating unit to the cooling unit when a temperature of the working fluid is above a threshold temperature; a sorption pump operatively coupled to the heating unit; and a thermal bus operatively coupled to the cooling unit.
 18. The polarizer system of claim 17, further comprising: a reservoir configured to house the working fluid; and an inlet valve operatively coupled to the reservoir and the plurality of serpentine capillaries and configured to permit flow of the working fluid between the reservoir and the plurality of serpentine capillaries.
 19. The polarizer system of claim 17, wherein the thermal switching device is configured to transfer heat from the sorption pump to the thermal bus when the thermal switching device is in an ON state.
 20. The polarizer system of claim 17, wherein the thermal switching device is configured to prevent transfer of heat from the sorption pump to the thermal bus when the thermal switching device is in an OFF state. 